About three-fifths of the population is of full or mixed African ancestry, including immigrants from the West Indies or their descendants, Cape Verdeans, and descendants of slaves brought from other parts of the New World or Africa before Britain outlawed the slave trade in 1807. Whites (people of European ancestry) constitute another one-third of the population and include those of British and American descent as well as descendants of Portuguese labourers from Madeira and the Azores who have immigrated to Bermuda since the mid-19th century. English is the official language, but some Portuguese is also spoken. Christianity predominates, and about one-sixth of the population is Anglican. Bermuda’s rate of population growth is low by world standards, comparable to that of the United States. Less than one-fifth of the population is younger than 15 years.